MOUSE ALPHA-1-MICROGLOBULIN BIKUNIN PRECURSOR - CDNA ANALYSIS, GENE EVOLUTION AND PHYSICAL ASSIGNMENT OF THE GENE NEXT TO THE OROSOMUCOID LOCUS

Alpha-1-Microglobulin (Alm) is a member of the lipocalin superfamily whereas bikunin is a Kunitz-type proteinase inhibitor. Alm and bikunin originate from a shared precursor. A comparison of mammalian cDNAs for the precursor indicates a highly conserved amino acid sequence along with muridae-specific deletions in both Alm and bikunin. In rodents, the gene for this precursor is less than 300 kb apart from the orosomucoid gene, another lipocalin gene. This precursor likely results from the assembly of two lipocalin and Kunitz-type genes, between 270 and 80 million years ago.